War correspondents often place themselves in harm’s way and, unavoidably, some die doing their jobs. Five have perished just this year in Libya, all of them photographers. Some wonder why photojournalists place their lives on the line.

These are images from Restrepo, a film about a U.S. Army platoon in Afghanistan’s deadly Korengal Valley. Shot over the course of a year, the documentary was nominated for an Academy Award this year. Co-director Tim Hetherington said in February he wanted people to connect with the war.

"It's not necessarily about moral outrage," he said. "It's about trying to understand that we're at war and try to understand the emotional terrain of what being at war means."

Hetherington was killed in April in Libya. His colleague and Restrepo co-director, Sebastian Junger, said Hetherington’s death shocked him, but he also accepts the risks.

"We don’t have a chance of having an equitable society or an equitable world without the free flow of information," said Junger. "And journalists play an indispensable role in that, and it’s a principle that I’m willing to some degree to risk my life for."

Associated Press Photo Director Santiago Lyon agreed that war reporting - without believing it contributes to a free society - is a waste of time. But he said some journalists may have other motivations.

"The experience of going to war or going to conflict is very compelling, because one’s life is in danger, and as Winston Churchill once famously said, ‘There is nothing so exhilarating in life as to be shot at without result.'"

This, said Lyon, offers a thrill and adrenaline rush for those photographers who seek excitement.

Photojournalists have witnessed combat since the 1850s, when they brought their photo labs to battlefields during the Crimean War. The pictured image from the U.S. Civil War is by Mathew Brady, a pioneer of American war photography. Motion pictures captured World War I, and today’s compact equipment allows journalists to work side-by-side with soldiers exchanging gunfire.

Graphic images hardly put an end to war. But Lyon said they can help to turn public opinion against it, as certain iconic images did during the U.S. war in Vietnam.

"But on another level, I think it’s a belief that if your picture can influence just one person and change their way of thinking, then in some way the exercise has been worthwhile," he said.

Junger said it is easy to describe a firefight. He characterizes it as a weird sort of football game with guns, drama and logic - kill them before they kill you. The difficulty, he said, is describing the moral intangibles. Junger related what an American military veteran once told him.

"'Those guys were trying to kill my brothers, and I killed them first.' There’s also this other level - why were any of us doing any of it at all, including them? What’s God going to say?’ And [the veteran] doesn’t even believe in God, and it still troubled him," said Junger.

Junger noted that images alone cannot fully describe combat, so he wrote the book War as a complement to his documentary. Santiago Lyon agrees. He says words add nuance to photography, and vice versa. And whether with camera or a pen, war correspondents risk their lives to tell the story of war.